bjoernager/rust
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Never inline naked functions

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The `#[naked]` attribute disabled prologue / epilogue emission for the
function and it is responsibility of a developer to provide them. The
compiler is no position to inline such functions correctly.

Disable inlining of naked functions at LLVM and MIR level.
This commit is contained in:
Tomasz Miąsko 2020-11-20 00:00:00 +00:00
parent fe982319aa
commit c2fb99984c
4 changed files with 45 additions and 4 deletions
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12
compiler/rustc_codegen_llvm/src/attributes.rs
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@ -25,7 +25,7 @@ use crate::value::Value;
/// Mark LLVM function to use provided inline heuristic.
#[inline]
fn inline(cx: &CodegenCx<'ll, '_>, val: &'ll Value, inline: InlineAttr, requires_inline: bool) {
fn inline(cx: &CodegenCx<'ll, '_>, val: &'ll Value, inline: InlineAttr) {
use self::InlineAttr::*;
match inline {
Hint => Attribute::InlineHint.apply_llfn(Function, val),
@ -35,7 +35,6 @@ fn inline(cx: &CodegenCx<'ll, '_>, val: &'ll Value, inline: InlineAttr, requires
Attribute::NoInline.apply_llfn(Function, val);
}
}
None if requires_inline => Attribute::InlineHint.apply_llfn(Function, val),
None => {}
};
}
@ -226,7 +225,14 @@ pub fn from_fn_attrs(cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value, instance: ty::
}
}
inline(cx, llfn, codegen_fn_attrs.inline.clone(), instance.def.requires_inline(cx.tcx));
let inline_attr = if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
InlineAttr::Never
} else if codegen_fn_attrs.inline == InlineAttr::None && instance.def.requires_inline(cx.tcx) {
InlineAttr::Hint
} else {
codegen_fn_attrs.inline
};
inline(cx, llfn, inline_attr);
// The `uwtable` attribute according to LLVM is:
//